Fig. 6. B38-CAP improves SARS-CoV-2-induced lung injury and respiratory dysfunction in hACE2 Tg mice.

a Experimental protocol; hACE2 Tg mice were i.t. infected with SARS-CoV-2 (2 × 10³ TCID₅₀), and then the mice were injected with B38-CAP (2 mg/kg i.p.) or vehicle once a day. b % Changes of body weight at 4 days after infection from before infection. Uninfected hACE2 Tg mice (control) treated with vehicle (n = 6), SARS-CoV-2 infected hACE2 Tg mice (SARS2) treated with vehicle (n = 5), and SARS2 treated with B38-CAP (n = 6) (b, c, e, g). c qRT-PCR of virus N gene expression in the lungs of hACE2 Tg mice. d Angiotensin II levels in the lung tissues (n = 6 mice for control + vehicle, n = 5 for SARS2 + vehicle and n = 5 for SARS2 + B38-CAP). e Wet to dry ratio of lung weight. f–g Lung histopathology. Representative images are shown (f). Bars indicate 1 mm (upper) and 100 μm (bottom). Lung injury scores were measured (g). h–i Lung function measurements. Elastance (h) and resistance (i) were measured at 4 days after SARS-CoV-2 infection in hACE2 Tg mice; control with vehicle treatment (n = 3), SARS2 with vehicle (n = 4), and SARS2 with B38-CAP (n = 4). All values are means ± SEM. One-way ANOVA with Sidak’s multiple comparisons test (b–e, g–i). Numbers above square brackets show P values. Independent experiments were performed two times (h–i) or three times (b–g), and consistent results were obtained.